Camera body and camera system using driving method information indicating capability of controlling focus lens

ABSTRACT

A camera body including a receiving unit that receives an operation by a user, an obtaining unit that obtains driving method information indicating a capability of controlling a focus lens from a mounted interchangeable lens, a body controller that controls the camera body and generates a control signal for controlling the interchangeable lens, and a sending unit that sends the control signal to the interchangeable lens. The body controller determines control of the interchangeable lens by referring to the driving method information to generate a control signal that instructs the interchangeable lens to perform the determined control. The receiving unit receives a selection of one driving method setting menu from a plurality of driving method setting menus, and makes a driving method setting menu, which uses a driving method other than the driving method indicated by the driving method information, unselectable.

TECHNICAL FIELD

The present invention relates to a camera system including aninterchangeable lens and a camera body, and more particularly, to acamera system capable of adjusting a focus state.

BACKGROUND ART

Patent Document 1 discloses an interchangeable lens type cameraapparatus. A lens unit mountable to the camera apparatus has drivingsystems for automatic focus adjustment and automatic exposure control.Also, the lens unit mountable to the camera apparatus has statusinformation of the lens unit. In this camera apparatus, a camera bodycontrols the lens unit by communicating various control information andstatus information between the camera body and the lens unit.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP 04-280239 A

SUMMARY OF INVENTION Problems to be Solved by the Invention

As described above, Patent Document 1 discloses only status informationof the driving systems for automatic focus adjustment and automaticexposure control as information held by the lens unit. However, withsuch a configuration, it is unknown whether, when predeterminedautofocus control is performed, the lens unit can accept the autofocuscontrol. Hence, with such a configuration, when autofocus control isperformed, the lens unit cannot be precisely controlled from the camera.For example, autofocus control by a driving method that is not supportedby the lens unit is instructed to the lens unit from the camera, thelens unit cannot carry out the instruction, thus causing a malfunction.

The present invention is made to solve the above-described problem, andhas an object to provide a camera system on which a camera body canprecisely control an interchangeable lens when autofocus control isperformed.

Means for Solving the Problems

In a first aspect a camera body to which an interchangeable lens ismountable is provided. The camera body includes an imaging unit that cancapture a subject image, a receiving unit that receives an operation bya user, an obtaining unit that obtains driving method information of theinterchangeable lens from the interchangeable lens, the driving methodinformation indicating a capability of controlling a focus lens, a bodycontroller that controls the camera body and generates a control signalfor controlling the interchangeable lens, and a sending unit that sendsthe generated control signal to the interchangeable lens. The bodycontroller determines control to be performed on the interchangeablelens, by referring to the driving method information obtained from theinterchangeable lens, and generates a control signal that instructs theinterchangeable lens to perform the determined control. The receivingunit receives a selection of one driving method setting menu from aplurality of driving method setting menus, and makes a driving methodsetting menu, which uses a driving method other than the driving methodindicated by the driving method information obtained by the obtainingunit, unselectable.

In a second aspect, a camera system including an interchangeable lensand a camera body is provided. The interchangeable lens includes a focuslens that changes a focus state of a subject image, a drive unit thatdrives the focus lens back and forth along an optical axis, a storageunit that stores driving method information indicating a capability ofcontrolling the focus lens, a sending unit that sends the driving methodinformation stored in the storage unit to the camera body, and a lenscontroller that controls an operation of the interchangeable lens. Thecamera body includes an imaging unit that can capture a subject image, areceiving unit that receives an operation by a user, an obtaining unitthat obtains the driving method information of the interchangeable lensfrom the interchangeable lens, a body controller that controls thecamera body and generates a control signal for controlling theinterchangeable lens, and a sending unit that sends the generatedcontrol signal to the interchangeable lens. The body controllerdetermines control to be performed on the interchangeable lens, byreferring to the driving method information obtained from theinterchangeable lens, and generates a control signal that instructs theinterchangeable lens to perform the determined control. The receivingunit receives a selection of one driving method setting menu from aplurality of driving method setting menus, and makes a driving methodsetting menu, which uses a driving method other than the driving methodindicated by the driving method information obtained by the obtainingunit, unselectable.

Effect of the Invention

According to the present invention, a camera body obtains driving methodinformation about driving methods that can be supported by aninterchangeable lens and determines a driving method to be used forautofocus control in the interchangeable lens, according to the drivingmethod information. By this arrangement, when autofocus control isperformed, the camera body can precisely control the interchangeablelens.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a camera system 1.

FIGS. 2A, 2B and 2C are schematic diagrams for describing driving methodinformation.

FIG. 3 is a chart for communication performed between a body and a lensduring an imaging preparation operation.

FIG. 4 is a flowchart for autofocus control.

FIG. 5 is a diagram of the back of a camera body 100.

FIG. 6 is a flowchart for autofocus control.

FIG. 7 is a flowchart for autofocus control during a zoom operation.

FIG. 8 is a flowchart for autofocus control during a zoom operation.

FIG. 9 is a diagram showing an example of driving method setting menus.

FIG. 10 is a diagram showing an example of driving method setting menus(in a state in which an unselectable driving method is displayed).

MODE FOR CARRYING OUT THE INVENTION

A lens interchangeable type camera system which is one embodiment of thepresent invention will be described below using the accompanyingdrawings. In the following embodiments, for a lens interchangeable typecamera system, a configuration will be described that enables preciselens drive control according to the type of autofocus control that canbe supported by an interchangeable lens.

First Embodiment

1-1. Configuration

1-1-1. Overview

FIG. 1 is a block diagram showing a configuration of a camera system 1in a first embodiment. The camera system 1 is configured by a camerabody 100 and an interchangeable lens 200 mountable to the camera body100. The camera system 1 can perform autofocus control by automaticallydriving a focus lens 230.

1-1-2. Configuration of Camera Body

The camera body 100 includes a CCD image sensor 110, a liquid crystaldisplay monitor 120, a camera controller 140, a body mount 150, a powersupply 160, and a card slot 170.

The camera controller 140 entirely controls the camera system 1, forexample, the CCD image sensor 110, according to an instruction from anoperation member such as a release button 130. The camera controller 140sends a vertical synchronizing signal to a timing generator 112. Inparallel with this, the camera controller 140 generates an exposuresynchronizing signal based on the vertical synchronizing signal. Thecamera controller 140 periodically and repeatedly sends the generatedexposure synchronizing signal to a lens controller 240 through the bodymount 150 and a lens mount 250. The camera controller 140 uses a DRAM141 as a work memory for performing a control operation or imageprocessing operation.

The CCD image sensor 110 captures a subject image incident thereonthrough the interchangeable lens 200 to generate image data. Thegenerated image data is digitized by an AD converter 111. The image datadigitized by the AD converter 111 is subjected to various imageprocessing by the camera controller 140. The various image processing asused herein includes, for example, a gamma correction process, a whitebalance correction process, a flaw correction process, a YC conversionprocess, an electronic zoom process, and a JPEG compression process.

The CCD image sensor 110 operates at timing controlled by the timinggenerator 112. The operations of the CCD image sensor 110 include astill image capturing operation, a moving image capturing operation, athrough image capturing operation, and the like. Switching between astill image capturing operation and a moving image capturing operationis performed by a user performing an operation on a still image/movingimage selection dial 131. Note that the through image is an image thatis not recorded in a memory card 171 after being captured. The throughimage is mainly a moving image and is displayed on the liquid crystaldisplay monitor 120 to cause a user to determine a composition of astill image.

The liquid crystal display monitor 120 displays an image represented bydisplay image data having been subjected to image processing by thecamera controller 140. The liquid crystal display monitor 120 canselectively display a moving image or a still image.

The card slot 170 allows the memory card 171 to be inserted thereinto.The card slot 170 controls the memory card 171 based on control by thecamera controller 140. The memory card 171 can store image datagenerated by image processing by the camera controller 140. For example,the memory card 171 can store JPEG image files. The memory card 171 canalso output image data or an image file stored therein. The image dataor image file outputted from the memory card 171 is subjected to imageprocessing by the camera controller 140. For example, the cameracontroller 140 decompresses image data or an image file obtained fromthe memory card 171 and generates display image data.

The power supply 160 supplies power to be consumed by the camera system1. The power supply 160 may be, for example, a dry battery orrechargeable battery. Alternatively, the power supply 160 may supply thecamera system 1 with power provided from an external source through apower cable.

The body mount 150 can be mechanically and electrically connected to thelens mount 250 of the interchangeable lens 200. The body mount 150 cansend/receive data to/from the interchangeable lens 200 through the lensmount 250. The body mount 150 sends an exposure synchronizing signalreceived from the camera controller 140, to the lens controller 240through the lens mount 250. The body mount 150 also sends other controlsignals received from the camera controller 140, to the lens controller240 through the lens mount 250. Further, the body mount 150 sendssignals received from the lens controller 240 through the lens mount250, to the camera controller 140. For example, the body mount 150 sendsto the camera controller 140 driving method information about drivingmethods for the focus lens 230 which is received from the lenscontroller 240 through the lens mount 250. Also, the body mount 150supplies power received from the power supply 160, to the entireinterchangeable lens 200 through the lens mount 250.

1-1-3. Configuration of Interchangeable Lens

The interchangeable lens 200 includes an optical system, the lenscontroller 240, and the lens mount 250. The optical system of theinterchangeable lens 200 includes a zoom lens 210, an OIS lens 220, andthe focus lens 230.

The zoom lens 210 is a lens for changing the magnification of a subjectimage formed by the optical system of the interchangeable lens 200. Thezoom lens 210 is configured by one or a plurality of lenses. A drivemechanism 211 includes a zoom ring operable by the user, and the like,and sends the zoom lens 210 an operation performed by the user to movethe zoom lens 210 in an optical axis direction of the optical system. Adetector 212 detects a position of the zoom lens 210 in the drivemechanism 211. The lens controller 240 obtains a detection resultobtained by the detector 212 and can thereby grasp the zoommagnification of the optical system.

The OIS lens 220 is a lens for correcting a blur of a subject imageformed by the optical system of the interchangeable lens 200. The OISlens 220 reduces a blur of a subject image on the CCD image sensor 110by moving in a direction to compensate for a shake of the camera system1. The OIS lens 220 is configured by one or a plurality of lenses. Anactuator 221 receives control from an OIS IC 223 and drives the OIS lens220 in a plane perpendicular to an optical axis of the optical system.The actuator 221 can be implemented by, for example, a magnet and aplanar coil. A position detection sensor 222 is a sensor that detects aposition of the OIS lens 220 in the plane perpendicular to the opticalaxis of the optical system. The position detection sensor 222 can beimplemented by, for example, a magnet and a Hall element. The OIS IC 223controls the actuator 221 based on a detection result from the positiondetection sensor 222 and a detection result from a camera shake sensorsuch as a gyro sensor. The OIS IC 223 obtains the detection resultobtained by the camera shake sensor, from the lens controller 240. TheOIS IC 223 also sends a signal indicating a state of an optical imageblur correction process to the lens controller 240.

The focus lens 230 is a lens for changing the focus state of a subjectimage formed on the CCD image sensor 110 through the optical system. Thefocus lens 230 is configured by one or a plurality of lenses.

A focus motor 233 drives the focus lens 230 to move back and forth alongthe optical axis of the optical system, based on control by the lenscontroller 240. By this, the focus state of a subject image formed onthe CCD image sensor 110 through the optical system can be changed. Inthe first embodiment, a DC motor can be used as the focus motor 233.However, in the present embodiment the focus motor 233 is not limitedthereto and can also be implemented by a stepping motor, a servo motor,an ultrasonic motor, and the like.

A first encoder 231 and a second encoder 232 are encoders that generatea signal indicating a driving state of the focus lens 230. The firstencoder 231 and the second encoder 232 can be implemented by, forexample, a rotor mounted on a rotating shaft of the focus motor 233 anda photocoupler. Here, the rotor is a disk having holes formed atpredetermined intervals. The photocoupler emits detection light from oneside of the rotor and receives light from the other side. Therefore, bythe rotor rotating, the photocoupler is alternately switched between ONand OFF states. The lens controller 240 has a counter 243 providedtherein. The counter 243 counts the number of switches between ON andOFF states from the photocoupler. The first encoder 231 and the secondencoder 232 are different in phase from each other. Therefore, amovement direction of the focus lens 230 for when the state of the firstencoder 231 is switched from OFF to ON can be determined. Specifically,the states of the second encoder 232 for when the state of the firstencoder 231 is switched from OFF to ON include an ON state and an OFFstate. Hence, when the state of the first encoder 231 is switched fromOFF to ON with the state of the second encoder 232 being ON, it isdetermined to be a forward rotation, and thus the counter 243 counts itas “+1”. When the state of the first encoder 231 is switched from OFF toON with the state of the second encoder 232 being off, it is determinedto be a reverse rotation, and thus the counter 243 counts it as “−1”. Byadding the counted values together, the lens controller 240 can graspthe amount of movement of the focus lens 230.

The lens controller 240 entirely controls the interchangeable lens 200such as the OIS IC 223 and the focus motor 233, based on control signalsfrom the camera controller 140. For example, the lens controller 240controls the focus motor 233 to cause the focus lens 230 to move backand forth along the optical axis by a predetermined driving method,based on a control signal from the camera controller 140. Also, the lenscontroller 240 receives signals from the detector 212, the OIS IC 223,the first encoder 231, the second encoder 232, and the like, and sendsthe signals to the camera controller 140. The lens controller 240performs communication with the camera controller 140 through the lensmount 250 and the body mount 150.

The lens controller 240 uses a DRAM 241 as a work memory upon control. Aflash memory 242 stores a program and parameters used for control by thelens controller 240. The parameters stored in the flash memory 242include driving method information pertaining to autofocus control thatcan be performed by the camera system 1. For example, an interchangeablelens that can perform autofocus control can perform autofocus control bymoving a focus lens back and forth along an optical axis by a pluralityof driving methods. Thus, in this case, the flash memory 242 storesdriving method information about a plurality of driving methods. Thedriving method information stored in the flash memory 242 will bedescribed in detail below.

1-1-4. Driving Method Information

FIGS. 2A and 2B are schematic diagrams for describing driving methodsfor the focus lens 230 controllable by the lens controller 240 in thefirst embodiment.

The camera system 1 in the first embodiment can perform autofocuscontrol by three types of driving methods. The first autofocus controlis control that performs an autofocus adjustment by moving the focuslens 230 back and forth along the optical axis at timing such as shownin FIG. 2A. This autofocus control is mainly used when a moving image iscaptured. This autofocus control is hereinafter referred to as “moviewobbling control”. The second autofocus control is control that performsan autofocus adjustment by moving the focus lens 230 back and forthalong the optical axis and stop at timing such as shown in FIG. 2B. Thisautofocus control is mainly used when, in capturing a still image, thefocus is continuously adjusted without interruption. This autofocuscontrol is hereinafter referred to as “continuous AF control”. The thirdautofocus control is control that performs an autofocus adjustment bymoving the focus lens 230 back and forth along the optical axis attiming such as shown in FIG. 2C. This is the so-called hill climbingautofocus control. This autofocus control is mainly used when a stillimage is captured. This autofocus control is hereinafter referred to as“single AF control”. These three types of autofocus control will bedescribed below.

When movie wobbling control as shown in FIG. 2A is performed, the camerasystem 1 moves the focus lens 230 minutely back and forth along theoptical axis every time a one-frame image is captured. By performing themovie wobbling control in this manner, the focus lens 230 continuouslymoves. By this arrangement, a smooth moving image can be capturedthroughout the entire shooting time. The camera system 1 calculates anevaluation value of autofocus operation (hereinafter, referred to as the“AF evaluation value”) of image data generated every time a one-frameimage is captured to generate image data. Specifically, a method isknown, which obtains a luminance signal from image data generated by theCCD image sensor 110, and adds up high-frequency components within theluminance signals of the whole image, to result in an AF evaluationvalue. As such, in every generation of two frames of image data, thecamera system 1 calculates the AF evaluation value in each of a state inwhich the focus lens 230 is moved to the subject side in the opticalaxis direction and a state in which the focus lens 230 is caused to moveto the side of the CCD image sensor 110. By comparing the two AFevaluation values, the camera system 1 determines whether to move thefocus lens 230 to the subject side or to the side of the CCD imagesensor 110 in a later cycle. By the camera system 1 thus moving thefocus lens 230 minutely back and forth along the optical axis, thecamera system 1 can continuously focus without interruption on a subjectimage when capturing a moving image.

When continuous AF control as shown in FIG. 2B is performed, the camerasystem 1 repeats a driving and stopping of the focus lens 230 every timea one-frame image is captured. The camera system 1 calculates an AFevaluation value of image data captured when the focus lens 230 isstopped. As such, the camera system 1 generates image data for fiveframes and calculates AF evaluation values of image data for threeframes among the five frames which are generated when the focus lens 230is stopped. By comparing the AF evaluation values at three points, thecamera system 1 can detect at any time a focus point which is morelikely to be reliable. By the camera system 1 repeating the driving andstopping of the focus lens 230 near the detected likely-to-be-reliablefocus point, the camera system 1 can continuously detect at any time afocus point which is more likely to be reliable.

When single AF control as shown in FIG. 2C is performed, the camerasystem 1 continuously drives the focus lens 230 in one direction fromany position of the interchangeable lens 200. The camera system 1periodically and continuously calculates an AF evaluation value inaccordance with the drive of the focus lens 230. The camera system 1continuously drives the focus lens 230 in one direction so long as theAF evaluation value keeps rising. When the AF evaluation value stopsrising and begins to fall, the camera system 1 determines that a focuspoint has been passed, and thus drives the focus lens 230 in a reversedirection. By this arrangement, the camera system 1 moves the focus lens230 to the focus point. The camera system 1 can detect a focus point bydriving the focus lens 230 in this manner.

By the way, to perform autofocus control by a plurality of types ofdriving methods in this manner, a driving program for driving the focuslens 230 by predetermined driving methods needs to be stored in theflash memory 242 in advance. Meanwhile, various interchangeable lensescan be attached to the camera body 100. For example, an interchangeablelens that does not support movie wobbling control as a focus lensdriving method can also be mounted. In such a case, if the camera body100 instructs the interchangeable lens 200 to perform movie wobblingcontrol, there is a risk that the camera system may malfunction.

In view of this, in the present embodiment, information about controlmethods that can be supported by the interchangeable lens 200 is storedin the interchangeable lens 200 so that the camera body 100 can refer tothe information. Specifically, the flash memory 242 of theinterchangeable lens 200 stores information (driving method information)about driving methods for the focus lens 230 used when autofocus controlis performed. For example, the flash memory 242 stores driving methodinformation indicating that the interchangeable lens 200 supports threedriving methods, that is, movie wobbling control, continuous AF control,and single AF control.

By thus storing driving method information in the flash memory 242, thecamera body 100 can obtain beforehand information about driving methodssupported by the interchangeable lens 200 from the interchangeable lens200 and thus can control the interchangeable lens 200 based on theobtained information about driving methods.

Note that in the present embodiment, the driving method information iscomposed of three bits. A first bit of the three bits indicates whethermovie wobbling control is supported, a second bit indicates whethercontinuous AF control is supported, and a third bit indicates whethersingle AF control is supported. Specifically, when a bit is “1” itindicates that the interchangeable lens 200 supports the correspondingautofocus control, and when “0” it indicates that the interchangeablelens 200 does not support the corresponding autofocus control. Thus,when only movie wobbling control is supported, the driving methodinformation is “100”. When only continuous AF control is supported, thedriving method information is “010”. When continuous AF control andsingle AF control are supported, the driving method information is“011”. Note that the configuration does not necessarily need to be likethis. The important point is that the driving method information isinformation indicating which autofocus control the interchangeable lens200 can support.

Note that the focus motor 233 is an example of a drive unit. The lenscontroller 240 is an example of a lens controller. The flash memory 242is an example of a storage unit. The CCD image sensor 110 is an exampleof an imaging unit. The still image/moving image selection dial 131 isan example of a receiving unit. A configuration including the cameracontroller 140 and the body mount 150 is an example of an obtainingunit. The camera controller 140 is an example of a body controller. Aconfiguration including the camera controller 140 and the body mount 150is an example of a sending unit. The liquid crystal display monitor 120is an example of a display unit.

1-2. Operations

1-2-1. Image Capturing Preparation Operation

First, the operation of the camera system 1 for imaging preparation willbe described. FIG. 3 is a diagram showing communication of signals todescribe an image capturing preparation operation of the camera system 1according to the first embodiment.

When the user turns on the camera body 100 mounted with theinterchangeable lens 200, the power supply 160 supplies power to theinterchangeable lens 200 through the body mount 150 and the lens mount250 (S11). Then, the camera controller 140 requests the lens controller240 for authentication information of the interchangeable lens 200(S12). Here, the authentication information of the interchangeable lens200 includes information on whether the interchangeable lens 200 ismounted and information on whether accessories are mounted. The lenscontroller 240 responds to the lens authentication request from thecamera controller 140 (S13).

Subsequently, the camera controller 140 requests the lens controller 240to perform an initialization operation (S14). In response to this, thelens controller 240 performs an initialization operation, such asresetting of a diaphragm and resetting of the OIS lens 220. The lenscontroller 240 then sends a response indicating that the lensinitialization operation is completed, to the camera controller 140(S15).

Then, the camera controller 140 requests the lens controller 240 forlens data (S16). The lens data is stored in the flash memory 242. Thelens controller 240 reads the lens data from the flash memory 242 andsends, as a response, the lens data to the camera controller 140 (S17).Here, the lens data includes characteristic values unique to theinterchangeable lens 200, such as a lens name, F-number, and a focallength.

Particularly, in the present embodiment, the lens data includes drivingmethod information about driving methods for the focus lens 230 that canbe supported by the interchangeable lens 200. By this arrangement, thecamera body 100 can obtain driving method information about drivingmethods for the focus lens 230 that can be supported by theinterchangeable lens 200, and the like, in an imaging preparation stage.Specifically, the camera body 100 can obtain at this stage informationindicating that the interchangeable lens can move the focus lens 230back and forth along the optical axis by three driving methods, that is,movie wobbling control, continuous AF control, and single AF control.

When the camera controller 140 recognizes the lens data of theinterchangeable lens 200 mounted to the camera body 100, the camerasystem 1 goes into a state in which an image can be captured. In thisstate, the camera controller 140 periodically requests the lenscontroller 240 for lens state data indicating a state of theinterchangeable lens 200 (S18). The lens state data includes, forexample, zoom magnification information by the zoom lens 210, positioninformation of the focus lens 230, and aperture value information. Inresponse to this request, the lens controller 240 sends, as a response,the requested lens state data to the camera controller 140 (S19).

1-2-2. Autofocus Control

Autofocus control of the camera system 1 on which image capturingpreparation has been completed in the above-described manner will bedescribed using FIGS. 4 and 5. FIG. 4 is a flowchart for autofocuscontrol of the camera system 1. FIG. 5 is a diagram of the back of thecamera body 100 in a state in which an alert is displayed.

When the camera body 100 is turned on, in an image capturing preparationstage, the camera body 100 obtains driving method information for thefocus lens 230 from the interchangeable lens 200 (S31). Then, at thisstage, the camera body 100 is on standby until a recording mode isselected by the user (S32). In the present example, it is assumed thatas the recording mode a mode for capturing a still image or a mode ofcapturing a moving image is selected.

When a recording mode is selected, the camera controller 140 determineswhether the selected recording mode is a still image recording mode or amoving image recording mode (S33).

If it is determined that the moving image recording mode is selected,then the camera controller 140 determines whether the interchangeablelens 200 can support movie wobbling control (S34). This determination ismade based on the driving method information obtained from theinterchangeable lens 200 in the image capturing preparation stage. Ifthe driving method information has information indicating that theinterchangeable lens 200 supports movie wobbling control, then it can bedetermined that the interchangeable lens supports movie wobblingcontrol. In the present embodiment, the interchangeable lens 200supports movie wobbling control.

If it is determined that movie wobbling control is supported, then thecamera controller 140 sends a control signal to the lens controller 240to move the focus lens 230 back and forth along the optical axis bymovie wobbling control (S35). By this arrangement, only when aninterchangeable lens that can support a recording mode instructed by theuser is mounted, a focus lens can be controlled by a driving methodcorresponding to the recording mode instructed by the user.

If, when a different interchangeable lens than the interchangeable lens200 is mounted, it is determined that movie wobbling control is notsupported, then the camera controller 140 controls the liquid crystaldisplay monitor 120 to provide display as shown in FIG. 5 (S36). Assuch, when the mounted interchangeable lens does not support moviewobbling control, the camera body 100 notifies the user of the factthrough display on the liquid crystal display monitor 120. By thisarrangement, the user can be notified that the attached interchangeablelens does not support a moving image recording mode. Also, the camerabody 100 does not instruct the interchangeable lens to cause the focuslens 230 to move back and forth along the optical axis by a drivingmethod that is not supported by the interchangeable lens. By this, therisk that a malfunction may occur in the interchangeable lens that doesnot support a moving image recording mode can be suppressed.

Note that in the present embodiment, the camera body 100 is configuredsuch that, when an interchangeable lens that does not support moviewobbling control is mounted, the camera body 100 provides alert displaythrough the liquid crystal display monitor 120 and does not instruct tomove a focus lens back and force along the optical axis in anunsupported drive cycle. However, the configuration is not necessarilylimited thereto. For example, when an interchangeable lens that does notsupport movie wobbling control is mounted, a moving image may becaptured by manually performing focus control. By this arrangement, evenwhen an interchangeable lens that does not support movie wobblingcontrol is mounted, a moving image can be captured.

Note also that although in the present embodiment, when aninterchangeable lens that does not support movie wobbling control ismounted, the camera body 100 provides on the liquid crystal displaymonitor 120 alert display indicating that the interchangeable lens doesnot support moving image shooting, the type of alert display is notnecessarily limited thereto. For example, even when an interchangeablelens that does not support movie wobbling control is mounted, if thecamera body 100 can perform moving image shooting by manual focus, thenthe camera body 100 may provide display indicating that moving imageshooting can be performed using manual focus.

On the other hand, if it is determined in step S33 that the still imagerecording mode is selected, then the camera controller 140 determineswhether an autofocus operation has been performed by the user (S37). Theautofocus operation is a half-press operation of the release button 130.

If it is determined that autofocus operation has been performed, thenthe camera controller 140 determines whether the interchangeable lens200 supports single AF control, based on the driving method information(S38). If it is determined that single AF control is not supported, thenthe camera controller 140 does not perform autofocus control and thefocus state of a subject image is adjusted by the user by the so-calledmanual focus (S39).

If it is determined that signal AF control is supported, then the cameracontroller 140 determines whether the interchangeable lens 200 supportscontinuous AF control, based on the driving method information (S40).

If it is determined that continuous AF control is supported, then thecamera controller 140 sends a control signal to the lens controller 240to perform single AF control on the focus lens 230 (S41). After a focuspoint of a subject image is detected by the single AF control, thecamera controller 140 sends, to the lens controller 240, a signal tocause the lens controller 240 to perform continuous AF control on thefocus lens 230 (S42). By this arrangement, the camera system 1continuously moves the focus lens 230 to the focus point until therelease button 130 is full-pressed by the user or until the focusoperation is completed.

If it is determined that continuous AF control is not supported, thenthe camera controller 140 sends a control single to the interchangeablelens 240 to perform single AF control on the focus lens 230 (S43). Aftera focus point of a subject image is detected by the single AF control,the camera controller 140 performs control to lock the focus lens 230 atthe detected focus point (S44). By this arrangement, in the camerasystem 1, the focus lens 230 is continuously locked in the lockedposition until the release button 130 is full-pressed by the user oruntil the autofocus operation is completed.

As such, in the present embodiment, the camera body 100 sends differentinstructions about the drive of the focus lens 230 to theinterchangeable lens 200, according to an instruction to capture a stillimage which is received from the user and the content of driving methodinformation obtained from the interchangeable lens 200. By thisarrangement, the most convenient autofocus control among autofocuscontrols that can be supported by the interchangeable lens 200 can beset.

Also, as such, in the present embodiment, the camera body 100 controlswhether to provide an instruction about the drive of the focus lens 230to the interchangeable lens 200, according to an instruction to capturea moving image which is received from the user and the content ofdriving method information obtained from the interchangeable lens 200.By this arrangement, an instruction to perform movie wobbling control ona focus lens can be prevented from being provided to an interchangeablelens that does not support moving image shooting.

Second Embodiment

A second embodiment will be described below using FIG. 6. Note thatdescription of the same configurations as those in the first embodimentis omitted (the same also applies to the following embodiments). Acamera system according to the present embodiment differs from thecamera system according to the first embodiment in part of autofocuscontrol.

2-1. Operations

2-1-1. Autofocus Control

FIG. 6 is a flowchart for autofocus control of the camera systemaccording to the present embodiment. The same steps as those in theautofocus control of the camera system in the first embodiment which isshown in FIG. 4 are denoted by the same reference signs and descriptionthereof is omitted.

The camera system of the present embodiment differs from the camerasystem of the first embodiment in steps (S50 to S53) performed after amoving image recording mode is selected and a camera controller 140determines that an interchangeable lens does not support movie wobblingcontrol. The steps will be described below.

If the camera controller 140 determines that the interchangeable lens200 does not support movie wobbling control (S34), then the cameracontroller 140 determines whether the interchangeable lens 200 supportscontinuous AF control, based on driving method information (S50).

If it is determined that continuous AF control is not supported, thenthe camera controller 140 controls a liquid crystal display monitor 120to provide alert display as shown in FIG. 5 (S51).

If it is determined that continuous AF control is supported, then thecamera controller 140 sends a control signal to a lens controller 240 toperform single AF control on a focus lens 230 (S52). After a focus pointof a subject image is detected by the signal AF control, the cameracontroller 140 sends a control signal to the lens controller 240 toperform continuous AF control on the focus lens 230 (S53). By thisarrangement, even when an interchangeable lens that does not supportmovie wobbling control is mounted, the camera system according to thepresent embodiment can capture a moving image by continuous AF control.According to this configuration, though the smoothness of a capturedmoving image is poorer than that of an image captured in movie wobblingcontrol, relatively accurate focus control can be performed, compared tothe case in which focus control is not performed at all.

Third Embodiment

In the present embodiment, a method of switching autofocus controlmethods during a zoom operation will be described. During a zoomoperation performed by the user, unless an autofocus operation by moviewobbling control is performed, changes in subject cannot be followed andthus an autofocus function does not operate properly. Hence, when aninterchangeable lens 200 does not support movie wobbling control, anautofocus operation is controlled to stop during a zoom operation. Thiscontrol will be described in detail below with reference to a flowchartin FIG. 7.

In FIG. 7, a camera controller 140 determines whether a zoom operationis being performed by the user (S61). If a zoom operation is beingperformed, then the camera controller 140 determines whether theinterchangeable lens 200 supports movie wobbling control, by referringto driving method information obtained from the interchangeable lens 200(S62).

If it is determined that the interchangeable lens 200 supports moviewobbling control, then the camera controller 140 sends a control signalto a lens controller 240 to move a focus lens 230 back and forth alongan optical axis by movie wobbling control (S64).

On the other hand, if it is determined that the interchangeable lens 200does not support movie wobbling control, then the camera controller 140sends a control signal to the lens controller 240 to stop an autofocusoperation (S63).

By the above-described control, autofocus control can be prevented frombeing erroneously performed on the interchangeable lens 200 that doesnot support movie wobbling control, during a zoom operation.

Fourth Embodiment

In the present embodiment, autofocus control for a case where movingimage shooting is performed will be described with reference to FIG. 8.

The camera controller 140 determines whether the interchangeable lens200 can support movie wobbling control, by referring to driving methodinformation obtained from the interchangeable lens 200 (S71).

If it is determined that the interchangeable lens 200 supports moviewobbling control, then the camera controller 140 determines whether theilluminance of a captured image is lower than a predetermined value(S72). If the illuminance of an image is lower than the predeterminedvalue, then the camera controller 140 sends a control signal to a lenscontroller 240 to perform continuous AF control on a focus lens 230(S73). The reasons why such control is performed will be describedbelow.

The reasons why continuous AF control is performed instead of moviewobbling control when the illuminance of a captured image is lower thanthe predetermined value will be described below. When the illuminance ofan image is low, noise increases. When movie wobbling control isperformed and AF evaluation values are calculated in a state in whichthere is a lot of noise, since the focus lens minutely moves back andforth at all times, the AF evaluation values are more susceptible tonoise. In addition, when AF evaluation values are calculated based onimages with a lot of noise, accurate evaluation values cannot beobtained. In view of these points, it is preferred that continuous AFcontrol be used when the illuminance of an image is low. In the case ofcontinuous AF control, since AF evaluation values are calculated withthe focus lens being stationary, the AF evaluation values are lesssusceptible to noise. Note that it is assumed that when theinterchangeable lens 200 supports movie wobbling control theinterchangeable lens 200 also supports continuous AF control.

If the illuminance of an image is higher than or equal to thepredetermined value, then the camera controller 140 sends a controlsignal to the lens controller 240 to perform movie wobbling control onthe focus lens 230 (S74).

By switching between autofocus controls based on the illuminance of animage in the above-described manner, accurate autofocus controlaccording to a shooting condition can be achieved.

On the other hand, if it is determined that the interchangeable lens 200does not support movie wobbling control, then the camera controller 140determines whether the interchangeable lens 200 supports continuous AFcontrol, by referring to the driving method information obtained fromthe interchangeable lens 200 (S75). If the interchangeable lens 200supports continuous AF control, then the camera controller 140 sends acontrol signal to the lens controller 240 to perform continuous AFcontrol on the focus lens 230 (S77). If the interchangeable lens 200does not support continuous AF control, then the camera controller 140does not perform autofocus control and the focus state of a subjectimage is adjusted by the user by the so-called manual focus (S76).

As such, even when the interchangeable lens 200 does not support moviewobbling control, if the interchangeable lens 200 supports continuous AFcontrol, then an autofocus operation can be performed by performingcontinuous AF control.

Other Embodiments

The above-described examples are described as various embodiments.However, the embodiments are not limited thereto. Hence, otherembodiments all together will be described below.

Although in the above-described embodiments a driving program is storedin the flash memory 242, the configuration is not necessarily limitedthereto. Specifically, a storage medium dedicated to storing a drivingprogram may be provided in the interchangeable lens 200 and a drivingprogram may be stored in the storage medium.

Although in the above-described embodiments the focus lens 230 alwaysperforms a wobbling operation when a moving image is captured, theconfiguration is not necessarily limited thereto. Specifically,autofocus control and manual focus control may be prepared as focus lenscontrol methods performed when a moving image is captured and thecontrol as described in the embodiments may be performed only when anautofocus control mode is selected.

Although in the above-described embodiments the configuration isexemplified in which the camera body 100 automatically determines adriving method to be used when performing autofocus control based ondriving method information obtained from the interchangeable lens 200,the driving method does not need to be automatically determined.Specifically, a means (e.g., a driving method setting menu or drivingmethod receiving dial) of receiving a selection of a driving method usedfor autofocus control from the user may be provided and a driving methodmay be determined based on a manual operation by the user. FIG. 9 showsan example of driving method setting menus displayed on the liquidcrystal display monitor 120. As shown in FIG. 9, a plurality of drivingmethod setting menus are displayed on the liquid crystal display monitor120. By the user moving a cursor 20 on a menu screen displaying theplurality of driving method setting menus, the user can select a drivingmethod used for autofocus control. At that time, the configuration maybe such that the camera body 100 does not accept a selection by theuser, of a driving method that cannot be supported by theinterchangeable lens 200, based on driving method information obtainedfrom the interchangeable lens 200. For example, when the interchangeablelens 200 does not support movie wobbling control, as shown in FIG. 10, aselection of movie wobbling control may not be accepted. By thisarrangement, autofocus control that cannot be supported by theinterchangeable lens is prevented from being selected by the user andthus the camera body 100 can be prevented from providing an instructionthat cannot be carried out by the interchangeable lens 200 to theinterchangeable lens 200, thus enabling to suppress occurrence of amalfunction. Note that, in the driving method setting menus in FIG. 9,“AF-S” indicates single AF control, “AF-C” indicates continuous AFcontrol, and “Movie” indicates movie wobbling control. In the presentembodiment, when AF-C is selected and the release button 130 ishalf-pressed by the user, the camera controller 140 causes the lenscontroller 240 to perform single AF control first to achieve focus andthen causes the lens controller 240 to perform continuous AF control tomaintain the focus state. In the present embodiment, when AF-S isselected and the release button 130 is half-pressed by the user, thecamera controller 140 causes the lens controller 240 to perform singleAF control. In the present embodiment, when Movie is selected, thecamera controller 140 causes the lens controller 240 to perform moviewobbling control. As such, in the present embodiment, there is a case inwhich one driving method is assigned to one driving method setting menuand a case in which a combination of a plurality of driving methods isassigned to one driving method setting menu. Note, however, that theconfiguration does not necessarily need to be like this. Theconfiguration may be such that only one driving method is assigned toone driving method setting menu or only a combination of a plurality ofdriving methods is assigned to one driving method setting menu.

Alternatively, when a selection of a driving method is received from theuser through a driving method setting menu and the like, if theinterchangeable lens 200 can support the selected driving method, thenthe camera body 100 may control the interchangeable lens 200 by theselected driving method, and if the interchangeable lens 200 cannotsupport the selected driving method, then the camera body 100 maycontrol the interchangeable lens 200 by any other supportable drivingmethod. For example, in the case where the interchangeable lens 200 cansupport single AF control but cannot support continuous AF control, whensingle AF control is selected by the user, the camera body 100 mayperform control to drive the interchangeable lens 200 by single AFcontrol. Alternatively, when continuous AF control is selected by theuser, the camera body 100 may perform control to drive theinterchangeable lens 200 by single AF control while providing on theliquid crystal display monitor 120 display indicating that continuous AFcontrol is not supported. By this arrangement, the camera body 100 canalways control the interchangeable lens 200 by a supportable drivingmethod.

Although in the above-described embodiments, when the camera system 1determines, based on obtained driving method information, that theinterchangeable lens 200 cannot support movie wobbling control, thecamera system 1 provides alert display on the liquid crystal displaymonitor 120, the process performed when control cannot be supported isnot limited thereto. Specifically, the configuration may be such thatwhen it is determined based on obtained driving method information thatthe interchangeable lens 200 cannot support movie wobbling control, aselection of a moving image recording mode made by the user is notaccepted. By this arrangement, unsupportable autofocus control isprevented from being selected by the user and thus the camera body 100is prevented from providing an instruction that cannot be carried out bythe interchangeable lens 200 to the interchangeable lens 200, enablingto suppress occurrence of a malfunction.

Although in the above-described embodiments the configuration is suchthat movie wobbling control is performed using two AF evaluation valuesand continuous AF control is performed using three AF evaluation values,autofocus control is not limited thereto. Specifically, movie wobblingcontrol may be performed using three or four AF evaluation values orcontinuous AF control may be performed using four or five AF evaluationvalues. In a word, movie wobbling control and continuous AF control maybe performed using AF evaluation values of any number.

Although in the above-described embodiments the configuration is suchthat when an interchangeable lens that supports movie wobbling controlis mounted, the camera body 100 performs movie wobbling control on thefocus lens 230, the configuration is not necessarily limited thereto.Specifically, when AF evaluation values are low and thus it isdetermined that the current position of the focus lens 230 is far off afocus point, single AF control may be performed first and then moviewobbling control may be performed. Accordingly, even when the focus lens230 is far off a focus point, the focus lens 230 can rapidly move to thefocus point by single AF control and thereafter the focus state cancontinue by movie wobbling control.

Although in the above-described embodiments autofocus control for a casewhere moving image shooting is performed is described, the autofocuscontrol is not necessarily limited thereto. Specifically, autofocuscontrol described in the embodiments may be used to capture a throughimage.

Although in the above-described embodiments, when moving image shootingis performed at the time when the interchangeable lens 200 that supportsmovie wobbling control is mounted to the camera body 100, autofocuscontrol is performed by movie wobbling control, the configuration is notnecessarily limited thereto. Specifically, the configuration may be suchthat, when moving image shooting is performed, in principle autofocuscontrol is performed using movie wobbling control, but when a stillimage shooting instruction, such as half-pressing the release button130, is accepted from the user autofocus control may be performed bysingle AF control.

Although in the above-described embodiments a configuration includingthe zoom lens 210 and the OIS lens 220 is exemplified, they are notessential components. Specifically, the idea of the embodiments can alsobe applied to a camera system mounted with a single focus lens having nozoom function and a camera system mounted with an interchangeable lenshaving no camera shake correction function.

Although in the above-described embodiments a camera body with nomovable mirror is exemplified, the configuration of the camera body isnot limited thereto. For example, a movable mirror may be included inthe camera body or a prism for splitting a subject image may be includedin the camera body. Alternatively, the configuration may be such that amovable mirror is included in an adapter instead of in the camera body.

Although in the above-described embodiments the CCD image sensor 110 isexemplified as an imaging device, the imaging device is not limitedthereto. For example, the imaging device may be configured by a CMOSimage sensor or NMOS image sensor.

INDUSTRIAL APPLICABILITY

The idea of the above-described embodiments can be applied to aninterchangeable lens that can perform autofocus control by at least onedriving method, a camera body to which such an interchangeable lens ismountable, and a lens interchangeable type camera system (specifically,a digital still camera, a digital movie camera, and the like).

Although the above describes specific embodiments, many other variants,modifications, and other uses are obvious to those skilled in the art.Therefore, the embodiments are not limited to the specific disclosuremade herein and can only be limited by the appended claims. Note thatthe present application relates to Japanese Patent Application No.2008-109870 (filed Apr. 21, 2008), the content of which is incorporatedherein by reference.

DESCRIPTION OF THE REFERENCE NUMERALS

-   1: CAMERA SYSTEM-   100: CAMERA BODY-   110: CCD IMAGE SENSOR-   112: TIMING GENERATOR-   130: RELEASE BUTTON-   140: CAMERA CONTROLLER-   200: INTERCHANGEABLE LENS-   230: FOCUS LENS-   231: FIRST ENCODER-   232: SECOND ENCODER-   233: FOCUS MOTOR-   240: LENS CONTROLLER

The invention claimed is:
 1. A camera body to which an interchangeablelens is mountable, the camera body comprising: an imaging unit that cancapture a subject image; a receiving unit that receives an operation bya user; an obtaining unit that obtains driving method information of theinterchangeable lens from the interchangeable lens, the driving methodinformation indicating a capability of controlling a focus lens; a bodycontroller that controls the camera body and generates a control signalfor controlling the interchangeable lens; and a sending unit that sendsthe generated control signal to the interchangeable lens, wherein thebody controller determines control to be performed on theinterchangeable lens, by referring to the driving method informationobtained from the interchangeable lens, and generates a control signalthat instructs the interchangeable lens to perform the determinedcontrol, and the receiving unit receives a selection of one drivingmethod setting menu from a plurality of driving method setting menus,and makes a driving method setting menu, which uses a driving methodother than the driving method indicated by the driving methodinformation obtained by the obtaining unit, unselectable.
 2. The camerabody according to claim 1, wherein the body controller generates thecontrol signal according to the operation by the user received by thereceiving unit and the driving method information obtained by theobtaining unit.
 3. The camera body according to claim 1, wherein whenthe body controller determines, by referring to the driving methodinformation obtained by the obtaining unit, that a driving methodcorresponding to the operation received by the receiving unit is notsupported by the interchangeable lens, the body controller does notgenerate a control signal for driving the interchangeable lens in thedriving method corresponding to the operation.
 4. The camera bodyaccording to claim 1, further comprising a display unit that can displayinformation, wherein the receiving unit receives a selection about adriving method for the interchangeable lens, and when the driving methodfor the interchangeable lens received by the receiving unit is notincluded in the driving methods indicated by the driving methodinformation obtained by the obtaining unit, the body controller controlsdisplay on the display unit to display an alert.
 5. A camera systemcomprising an interchangeable lens and a camera body, theinterchangeable lens comprising: a focus lens that changes a focus stateof a subject image; a drive unit that drives the focus lens back andforth along an optical axis; a storage unit that stores driving methodinformation indicating a capability of controlling the focus lens; asending unit that sends the driving method information stored in thestorage unit to the camera body; and a lens controller that controls anoperation of the interchangeable lens, the camera body comprising: animaging unit that can capture a subject image; a receiving unit thatreceives an operation by a user; an obtaining unit that obtains thedriving method information of the interchangeable lens from theinterchangeable lens; a body controller that controls the camera bodyand generates a control signal for controlling the interchangeable lens;and a sending unit that sends the generated control signal to theinterchangeable lens, wherein the body controller determines control tobe performed on the interchangeable lens, by referring to the drivingmethod information obtained from the interchangeable lens, and generatesa control signal that instructs the interchangeable lens to perform thedetermined control, and the receiving unit receives a selection of onedriving method setting menu from a plurality of driving method settingmenus, and makes a driving method setting menu, which uses a drivingmethod other than the driving method indicated by the driving methodinformation obtained by the obtaining unit, unselectable.
 6. The camerasystem according to claim 5, wherein the body controller generates thecontrol signal according to the operation by the user received by thereceiving unit and the driving method information obtained by theobtaining unit.
 7. The camera system according to claim 5, wherein whenthe body controller determines, by referring to the driving methodinformation obtained by the obtaining unit, that a driving methodcorresponding to the operation received by the receiving unit is notsupported by the interchangeable lens, the body controller does notgenerate a control signal for driving the interchangeable lens in thedriving method corresponding to the operation.
 8. The camera systemaccording to claim 5, wherein the camera body further comprises adisplay unit that can display information, and the receiving unitreceives a selection about a driving method for the interchangeablelens, and when the driving method for the interchangeable lens receivedby the receiving unit is not included in the driving methods indicatedby the driving method information obtained by the obtaining unit, thebody controller controls display on the display unit to display analert.
 9. A camera body to which an interchangeable lens is mountable,the camera body comprising: an imaging unit that can capture a subjectimage; an obtaining unit that obtains at least one focus driving methodfrom the interchangeable lens mounted to the camera body, the at leastone focus driving method indicating a focus driving capability of theinterchangeable lens; a display unit that displays a plurality of focusdriving methods including the at least one focus driving method receivedby the obtaining unit from the interchangeable lens; wherein the atleast one focus driving method received by the obtaining unit from theinterchangeable lens is displayed on the display unit as beingselectable by a user, and each of remaining focus driving methods amongthe plurality of focus driving methods which has not been received bythe obtaining unit from the interchangeable lens is displayed on thedisplay unit as being unselectable by the user.
 10. The camera bodyaccording to claim 9, wherein the plurality of focus driving methodsinclude a single auto-focus control, a continuous autofocus control anda manual focus control.
 11. A camera system comprising aninterchangeable lens and a camera body, the interchangeable lenscomprising: a focus lens that changes a focus state of a subject image;a drive unit that drives the focus lens back and forth along an opticalaxis; a storage unit that stores at least one focus driving methodindicating a focus driving capability of the focus lens; a sending unitthat sends the at least one focus driving method stored in the storageunit to the camera body; and a lens controller that controls anoperation of the interchangeable lens, the camera body comprising: animaging unit that can capture a subject image; an obtaining unit thatobtains the at least one focus driving method from the sending unit ofthe interchangeable lens; a display unit that displays a plurality offocus driving methods including the at least one focus driving methodreceived by the obtaining unit from the sending unit of theinterchangeable lens; wherein the at least one focus driving methodreceived by the obtaining unit from the sending unit of theinterchangeable lens is displayed on the display unit as beingselectable by a user, and each of remaining focus driving methods amongthe plurality of focus driving methods which has not been received bythe obtaining unit from the sending unit of the interchangeable lens isdisplayed on the display unit as being unselectable by the user.
 12. Thecamera system according to claim 11, wherein the plurality of focusdriving methods including a single auto-focus control, a continuousautofocus control and a manual focus control.